The present invention relates to a hinge assembly for a cover and more particularly to a hinge assembly used to connect a cover to a frame of a personal digital assistant or the like.
Most personal digital assistants (PDA""s) have protective plastic covers over their screens to prevent damage thereto. When such covers are used it is important that they can be securely held in either the opened or closed position. To this end, some cover arrangements for PDA""s have included catches or stoppers which maintain the cover in the required open or closed position. However, it has been found that over time and with continued use these catches tend to wear thereby preventing the cover from being maintained in the open position. This is a very annoying for the user because the dropping cover will then tend to obscure the user""s visibility of the PDA""s screen.
U.S. Pat. No. 5,996,178 describes a hinge suitable for use in a foldable electronic device. The hinge system described in U.S. Pat. No. 5,996,178 relies on axial force from the compression spring to cause rotation of the cover. The hinge system is quite complicated and involves a considerable number of parts. The configuration of the hinge system is also such that additional axial space is required to locate the hinge system.
The present invention seeks to provide an improved hinge assembly for the cover of a PDA or the like which securely maintains the cover in the desired open or closed position, that has a reduced number of component parts and which is compact in design.
According to a first aspect of the present invention there is provided a hinge assembly for connecting a cover to a device, said assembly including a boss member on which a biasing means is arranged to be mounted, a cover connection member arranged to be mounted on said device, said connection member having a first end portion including cam means arranged to interact with at least one portion of said biasing means and a second portion to which said cover is arranged to be connected.
Preferably, said biasing means is a torsion spring.
Preferably, the device has a side wall and the cover connection member is arranged to extend through an aperture in the side wall.
Preferably, the torsion spring includes a circular portion and a pair of elongate portions which extend substantially parallel to one another. As an alternative to the torsion spring including a circular portion, it may include an oval shaped portion.
The boss member preferably includes a body portion and an enlarged end portion. The torsion spring is arranged to be mounted on the boss member so that the circular portion of the torsion spring is located on the body portion of the boss member. The enlarged portion of the boss member serving to prevent the torsion spring from disengaging from the boss member.
Preferably, the cam means of the connection member means includes first and second pairs of opposed parallel surfaces. The first and second pairs of opposed surfaces extending perpendicularly to each other and preferably with each adjacent first and second surface being joined by a curved joining surface.
The first portion of the connection member also includes means to engage against the torsion spring to thereby prevent the connection member from inadvertently disengaging from the aperture formed in the side wall. The engagement means preferably includes an enlarged portion adjoining the cam means and arranged to contact against at least one of the elongate portions of the torsion spring so as to thereby prevent the connection member from returning through the aperture formed in the side wall.
The second portion of the connection member preferably includes first and second cylindrical portions. The aperture located within the side wall of the device is preferably configured to receive said first and second cylindrical portions of the connection means so that the connection means can rotate there within.
The configuration of the first and second cylindrical portions and the aperture being arranged to prevent the connection member from passing all the way through the aperture.
The first cylindrical portion is preferably located adjacent the cam means and has a reduced diameter as compared with the diameter of the second cylindrical portion.
The cover and an end part of the second cylindrical portion of the connection member preferably include complimentary shaped connectors to enable the cover to be connected to the connection member. The complimentary shaped connectors preferably include male and female connectors. The male connector is preferably located on the cover and may adopt a xe2x80x9ccrossxe2x80x9d or xe2x80x9cminusxe2x80x9d cross-sectional configuration. The male or female connector on the cover is preferably formed on a hinge member which extends from the cover. The cover preferably includes a pair of hinge members, each hinge member having a connector mounted or formed thereon which is arranged to be received in a respective complimentary connection member formed in respective side walls of the device.
The boss member and the connection member are preferably made from a plastics materials. The cover is also preferably made from a plastics material.
According to a second aspect of the invention there is provided an assembly including a device having opposed side walls, a cover arranged for connection to the device and at least one hinge assembly, said at least one hinge assembly including a boss member on which a torsion spring is arranged to be mounted, a cover connection member arranged to be mounted on one of said side walls, said connection member having a first portion including cam means arranged to interact with at least one portion of said torsion spring and a second portion to which said cover is arranged to be connected.
Preferably, the assembly includes a pair of hinge assemblies.
According to a third aspect of the invention there is provided a hinge assembly for connecting a cover to a device, the cover being arranged to move between a fully open and a fully closed position, the hinge assembly including a cover connection member arranged to join said cover to said device and biasing means arranged to engage with a portion of said connection member and to bias said cover towards either said fully opened or said fully closed position depending on the orientation of the connection member.